http://imid.me/blog/2013/07/22/building-android-rest-client-applications-efficiently-number-1/
http://wangchao0721.wordpress.com/2011/06/02/android-rest-client%E6%9E%B6%E6%9E%84%E5%AE%9E%E8%B7%B5-%E7%AC%AC%E4%B8%80%E7%AF%87/
http://wangchao.de/category/rest/
http://www.oschina.net/code/snippet_273190_16540